Bound
by Kalira69
Summary: Keith never knew . . . until the Kerberos Mission launched and took Shiro away. (Soulmate AU; Written for Sheith Month, Day 31)


Written for Day 31 of Sheith Month: Pain.

Final day of Sheith Month! I actually intended to write for the other prompt for today (Hero), and then an idea jumped me, I jotted down some notes that turned into the beginnings of a story, and then realised it fit today's prompt _perfectly_. (Although now I'm ending the Event on these feels I feel like I need to write something happier for Sheith again soon. XD)

* * *

Keith never knew until he stood in the small crowd, fighting a smile and fighting tears as he watches the ship disappear, carrying Shiro on the first arc of a long, long journey. He is happy for Shiro, who had been thrilled and so excited with the mission, but . . . Keith is going to miss him desperately over the long months until he returns.

It is hours after the launch of the Kerberos mission that Keith begins to feel a prickling pain between his shoulder blades, creeping up his neck, sinking into his chest. He dismisses it as he goes somewhat numbly about his day - how can it be a normal day when he spent the morning watching Shiro _leave_? - and finally to bed, thinking sleep will ease the ache. It's likely caused by stress anyway. He is uneasy and upset, but exhausted, and sleep is not too long in coming all the same.

When he wakes the ache is actually worse. Keith sets his jaw against the dull spike of pain that keeps him stiff and tense as he rises, and fights to relax, knowing tensing up will only make the pain intensify as his muscles knot. It doesn't particularly help, but he shoves down the pain and steadfastly ignores it as he pulls on a clean uniform and heads to the first class of his day.

The pain lingers, steady and never-fading, growing little by little more intense. It is days after the Kerberos mission launch before Keith suddenly realises what it may be. Days more before he admits to himself that it _must_ be, that there is no other explanation for this.

Weeks pass and the pain heightens until Keith is hard-pressed not to scream at the agony of _existing_. Sleep comes uneasily and slow each night, and when it finally takes him it is deep but not restful. Waking feels like a nightmare and it takes him long minutes to drag himself into motion, to rise and begin his day, slow and stiff. He is peripherally aware he's grown thinner, his face pale save for the deep shadows around his eyes when he catches glimpses of himself. He vaguely notices the occasional concerned look from instructors and commanding officers, but no one asks anything that cannot be put off with a clipped 'I'm fine' and a flat look.

Dragging himself through each day with the knowledge that there is nothing else he _can_ do, Keith thinks of Shiro on that small ship flying so very far away - and for so _long_ \- and _hurts_ , somewhere different, somewhere more nebulous and less physical than the pain that now wraps around his heart and lights up the length of his spine, creeps through every limb, thinking of Shiro suffering the same.

It reaches a plateau, eventually. He hadn't been sure it would. The pain now grows no worse, and Keith simply continues, as he has since the departure of the Kerberos mission. His condition doesn't change - he is leaner than he has ever been, and he sleeps poorly when he sleeps at all - but Keith has learned how to manage it, to continue through his days. It barely seems anything but commonplace, now. The pain he carries overwhelms everything else, makes it hard to remember there _was_ a time when it was absent.

The time drags on, and Keith has little energy to spare for anything but the essentials, but from time to time he goes up to the roof alone. Watches the stars and looks out as though he can see to the furthest reaches of the system, to where Shiro is heading, and thinks longingly of Shiro's return, though it is still months away.

Keith is blindsided by the news that the Kerberos mission has failed and all three of those aboard are dead, disappeared into the wasteland of space along with the ship. He stares at the lieutenant who had told him the news, then looks at the screen playing an announcement beyond the man.

Keith is _blindsided_.

Because the agony didn't cease, and didn't spike to a killing wave. Keith _hurts_ , deep down, wound through every muscle and bone and carved deep into his heart, as he has for months now, since the pain stopped growing and settled in. He supposed, when he realised it was no longer worsening, that it reached the point to be as badly as one _can_ hurt, without dying of it, from the absence of one's soulmate.

Shiro is still alive, wherever he is, whatever happened to the Kerberos mission, because Keith's entire being is raw with the pain of being split from him. If Shiro were to die, the agony would cease . . . or it would swell up and take Keith along with his soulmate. No one knows which way the bond will take them until it happens, though the former is more common.

Keith tries to take it to those in charge at the Garrison, tries to explain without explaining that he _knows_ Shiro is alive, that whatever happened there is no way he's been killed. Missing is deadly and terrifying, at the outer reaches of the system, and by the time anyone could reach Kerberos to look for them. . . But Shiro is _not_ dead. Not yet. Not now.

They don't listen, and Keith can't- he doesn't have the words, the _ability_ to make them, to draw the right lines.

He doesn't think he ever did, but with the pain dug into his bones and searing in his heart Keith has very little of himself left to spare. It makes him sharp and curt and antagonistic where he thinks perhaps he was only awkward, withdrawn, strange before. Keith wraps himself around the pain of his missing soulmate and the rest of the world is so far away.

Iverson tells him Shiro is dead and to let it go and get back to his studies, mourn his friend and don't make the same mistakes Shiro did.

Keith can't be sure he wouldn't have reacted the same way before the soulmate pain wrecked him, drew off all his willpower to channel into mere survival. Perhaps he would have controlled himself. Perhaps not.

He lunges across the desk and punches Iverson, and despite his condition it takes Iverson plus two more officers to drag Keith away. He is panting and angry and the fury and the pain combine to steal any words from his tongue. He says nothing as he is dragged off the grounds of the Galaxy Garrison, and collapses beside the crates of his belongings in the dirt as soon as he is left alone, shaking and not sure if it is anger, pain, shock, or his gnawing fear for Shiro causing it.

He doesn't remain there in his shattered heap for long - Keith has always been good at pulling himself together, quashing down anything that might hold him back, and carrying on. Even when he doesn't want to be. Sometimes - too often - it has been all he has.

He knows where he's going, and with his hoverbike it isn't a hard trip - not for Keith, anyway; sideslipping rock formations and speeding straight across the desert. He knows exactly where he's going, through the ever-shifting landscape. The little cabin is a bit dustier, a bit more worn, a bit less inviting, than it was when last he was here - he hasn't returned since he brought Shiro here for a weekend of leave to make him _calm down_ after finals - but . . . it's home. At least as much of one as Keith has ever had.

He settles the hoverbike by the porch, hauls his belongings inside, and just . . . sits, crumpled.

The pain drags at Keith the same way it has for months now. Wherever Shiro is, whatever happened to the Kerberos mission and the three lost people who had been aboard, Shiro is still alive. Keith clings to that, though he has nothing else.

Over the following days Keith falls into a new sort of routine. He no longer has classes, training, sims to get to, there are no longer people to face and placate, but even in this condition he is not the kind of person who can just sit, no matter how much he hurts or how lost he feels. He begins wandering the desert, on foot and on his hoverbike, and in between he scours all the reports and information he can get his hands on, legally and not, for any news or sign of the Kerberos mission.

Shiro would probably tell him his obsessive focus on both is unhealthy, but Shiro isn't here. Keith would do anything to hear his hypocritical scolding again right now, but all Keith has is the mysterious pull in the desert - the odd warning that he has calculated out to a day that is rapidly approaching - and the constant search for information and the pain that lives deep in every fibre of his body.

On the day the glyphs had indicated Keith _jolts_ awake suddenly, panting, heart racing.

He doesn't hurt.

. . .he _doesn't hurt_.

Keith pushes himself up and his breath catches as he wonders if he's finally died, if the pain _could_ grow worse despite all he'd thought and take him with it, or worse, if _Shiro_ \- Then Keith realises that it isn't . . . _gone_. The pain is still coiled close around his heart and all but sparking along his bones but it is _so much less_ now he almost doesn't feel it.

Shiro. Keith rasps his name on a choked breath and scrambles off the couch, clumsy with the strange lessening of the pain he carries, the pounding of his heart, the uncertainty. He remembers the warning, the glyphs he read, and he . . . wonders. He wonders where Shiro _is_ because he has to be close, _coming_ closer, and Keith can't remember exactly how long ago it was the pain had been so light as this, how far the Kerberos mission had gone.

He heads into the desert, all but laughing with somewhat hysterical relief even as he feels a spark of apprehension. What is he going to find? Where is Shiro? _What happened?_

When he finds the wreckage of an unfamiliar ship, and the _Garrison_ climbing all over the site, Keith's eyes narrow and he growls low in his throat. He skims the perimeter, watching, and makes a plan.

It's easy - easier than he might have thought. Perhaps Shiro was right and flying isn't his only talent, perhaps the ease with which tactics come to him is something else he should have pursued, or perhaps the Garrison is just sloppy in this, not truly expecting a threat. Not an external one, anyway.

Not expecting Keith to crash into the centre of their _experimental containment mobile unit_ and Keith can feel his body lightening as he runs; it makes taking down the Garrison techs in his way even easier than anticipated. Until he reaches the large room at the centre of the mobile base and his heart nearly stops.

He forges onward and in a few moments he's at the side of the table, his throat locking as he pulls down his mask and stretches out a hand tentatively. His fingertips brush Shiro's face - because it _is_ Shiro, whatever has been done to him, by the Garrison or wherever he was before, it _is_ \- and Keith nearly collapses as the pain just-

Stops.

The brush of skin on skin, even so slight as Keith's fingertips on Shiro's jaw, and it's gone as though it had never been, Keith's body practically _fizzing_ with the absence. Shiro is still not awake, _aware_ , but his body loses a bit of the tension it had held even in his drugged state.

Keith snarls quietly as he frees Shiro from his bindings - Shiro, _Shiro_ , they bound _Shiro_ to the table like he was some kind of experiment, an animal, an _enemy_ , and Keith wishes he could go back and take them down again. He pulls Shiro up and is surprised to suddenly not be alone any more. It's clear the newcomers aren't Garrison scientists or security officers, but Keith is still hard-pressed not to lash out at them as well.

He lets them tag along, somewhat exasperated, and leads the Garrison forces on a merry chase, feeling almost lightheaded with the absence of the agony he's been living with for so long. He can't help but keep stealing glances at Shiro as he flies, once they are no longer _quite_ so pressed - the pursuit left behind when they couldn't match his tight flying and _wouldn't_ follow the controlled plummet he'd taken.

When they reach the cabin Keith abandons the hangers-on he picked up arguing over something and settles Shiro inside on the couch. Keith sits on the table beside it, unable to drag himself away from Shiro, wrapping his hands around Shiro's wrist and twining his fingers together. He can feel Shiro's pulse against his fingertips.

He bows his head, almost resting his brow against Shiro's ribs. He still feels a little dizzy from the lack of the pain he's grown so used to carrying, always. Beyond that his mind is whirling but above all else he can't help but focus on-

 _Shiro is back._

Keith swallows down a thick lump in his throat, tears of shock and relief prickling behind his eyes. He whines quietly, shivering.

Distracted - overwhelmed - as he is, he still doesn't miss when Shiro stirs. He bolts upright, sliding right to the edge of the stone tabletop and leaning closer, forcing himself to loosen his grip at least a little. "Shiro?" he calls softly.

Shiro jerks, lashes fluttering as he groans. His limbs begin to twitch and Keith strokes the back of his hand soothingly. Shiro's eyes open after another minute or two, and he shakes his head, seemingly struggling to focus. His eyes land quickly on Keith's face as he leans forward and Shiro's eyes go wide, then his expression crumples. " _Keith._ " he rasps.

Keith swallows hard, clasping Shiro's hand. "Shiro, you're- You're back." he says weakly, his own voice hardly steady.

He vaguely hears the sound of the wind outside growing louder, the barely-there creak of the door, but Keith can't bear to tear his gaze away from Shiro even as he hears low muttering outside. "Give them a minute!" There's a soft scuffle and the door clicks shut and Keith still can't look anywhere but Shiro's _face_ \- soft grey eyes, faint stress lines he didn't have before he left, the broad scar across his nose.

"Keith. . . I'm sorry." Shiro says, and Keith settles back a fraction, thrown.

"What?" Keith asks after a moment, when it still makes no sense, fingertips stroking Shiro's hand along the line of one strong bone.

"I'm so sorry," Shiro struggles to sit up and Keith leans forward to help him, "if I had known- If I'd- I would never have left, not without you."

Keith was still struggling to understand until that last- "Oh, _Shiro_. I didn't know either, and you- It wasn't-" He can't quite keep his voice steady as he chokes on the emotion welling up from his chest.

"You've been _hurting_ , all this time, because of me." Shiro says softly and Keith just shakes his head, releasing Shiro's hand and lunging for him.

"Shiro, you _idiot_." Keith mutters against his neck as Shiro goes stiff, then wraps him up in a tight embrace. Shiro shakes in his arms, burying his face against Keith's hair as he takes hitching breaths, and Keith stabilises himself a little more on the edge of the couch and sways gently, rubbing Shiro's back. "I love you," he says, because it's _easy_ after months on end of aching with the absence of the other half of his soul, "I'm just glad you're safe, and here." He tightens his arms around Shiro.

Shiro lets out a hitching little sob that could be a laugh and holds on tighter. "Me too. Keith, I-" His voice breaks.

Keith hums softly, leaning into Shiro a little more and rubbing up and down his spine as he cries into Keith's hair.

Shiro, his _soulmate_ , is safe and back and here in his arms and Keith is _never_ going to let him away alone again.

* * *

Obviously neither of the boys realised they were soulmates before, and the pain of being separated naturally only happens if you've already _met_ /been close with your soulmate. And before Shiro departed on the Kerberos mission they had never been more than a very short distance apart since they met, so the pain never so much as began to prickle at either of them.

I actually didn't think I'd write this particular soulmate AU at any point . . . and yet.


End file.
